Abstract: A multiroom air conditioner has a plurality of indoor heat exchangers connected to a single outdoor heat exchanger. A reversible expansion valve is installed on a liquid-side branch pipe for each of the indoor heat exchangers, and a solenoid valve is installed on a gas-side branch pipe for each indoor heat exchanger. Temperature sensors are provided on the liquid-side branch pipes, on the gas-side branch pipes, and on the outlet side during cooling of the outdoor heat exchanger. A pressure sensor or a temperature sensor detects the saturation temperature on the high-pressure side of the compressor. Based on the saturation temperature on the high-pressure side of the compressor, the temperature on the outlet side during cooling of the outdoor heat exchanger, and the temperatures in the liquidside branch pipes, a controller controls the expansion valves so as to obtain a target degree of subcooling during cooling and heating.